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Letters of Interpretation

PHMSA has published several Frequently Asked Questions (FAQs) documents on programmatic topics. Please review these documents here at: https://www.phmsa.dot.gov/about-phmsa/phmsa-faqs.

Additionally, Office of Hazardous Materials Safety has published Hazardous Materials FAQs based on letters of interpretation on the following topics:

Office of Hazardous Materials Safety: For questions about transporting hazardous materials, needing clarifications of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180), or requesting a formal letter of interpretation, please go to the Hazardous Materials Information Center (HMIC) page for contact information (phone and email address). Pending interpretation letters that are under review by the Office of Hazardous Materials Safety can be found at Pending Hazardous Materials (Hazmat) Interpretations.  

Office of Pipeline Safety: A written regulatory interpretation, response to a question, or an opinion concerning a pipeline safety issue may be obtained by submitting a written request to the Office of Pipeline Safety (PHP–30), PHMSA, U.S. Department of Transportation, 1200 New Jersey Avenue SE., Washington, DC 20590–0001 or at the email address: pipeline_interp_submittal@dot.gov. In addition to email address, the requestor must include his or her return address and should also include a daytime telephone number. Requests should be submitted at least 120 days before the time the requestor needs a response. Note: electronic submission is provided as alternative to the 49 CFR Part 190.11(b) mail-in requirement.

Interpretation letters under review are available at the Office of Pipeline Safety’s Interpretation Review page. To submit comments on an interpretation under review, proceed to the Interpretation Review page, locate the interpretation to comment on, and click the appropriate link to submit a comment on the corresponding interpretation. Comment submissions will be accepted for 30-days after the interpretation letter is posted.

This section of the website below provides the ability to find regulations information including regulations parts, content of sections, and interpretations for regulations sections. A list of parts, identified by the part number and subject is also provided. To browse sections by part, click on the subject link below. You will be taken to the eCFR website to view sections for a part.

The eCFR is also searchable by keyword and other available options on the eCFR website. To search and browse regulations using the eCFR website, use the link below. For assistance, please send an email to PHMSA.Webmaster@dot.gov.

Search the eCFR

Interpretations Reference #

Search Tip: Use quotation marks to search for commonly used phrases, such as “gas transmission” or “cargo tank motor vehicle.”
E.g., 02/09/2021
E.g., 02/09/2021
Ref ID: Date Company Name Individual Name Response Document
05-0103 Office of Hazardous Materials Enforcement (PHH-46) Mr. William Stevens Sr. View
04-0285 The Field Museum Ms. Jolynn Parchen View
05-0048 NSWC Crane Division Mr. Charles Kimble View
05-0044 FedEx Express Corporate Safety Department Mr. Marvin Sudduth  View
05-0037 Brand-Nu Laboratories, Inc. Mr. Paul Lombardo View
05-0089 Georgia Department of Motor Vehicle Safety Capt. Bruce Bugg View
PI-05-0100 Atlanta Gas Light Company Mr. Richard Lonn View
PI-05-001 Sempra Energy William A. Calders View
05-0063 A. Duie Pyle, Inc. Mr. Rich K. Kaczynski View
05-0065 PurePak Corporation Mr. David Giaccio View
05-0082 United States Regulatory Commission Mr. David Pstrak View
05-0052 Duratek Training Services Ms. Kathryn Pacha View
05-0033 Hazmat Seminars Mr. Paul Shelton View
04-0057 Saf-T-Pak, Inc. Mr. Art Rutledge View
05-0072 Burdette & Associates Mr. Mike Burdette View
04-0280 Holman Fenwick & Willan Mr. Rory Butle View
05-0050 Arkema Inc. Ms. Christina M. Kurtz View
05-0061 Spurrier Chemical Companies, Inc. Mr. Bruce F. Lavery View
05-0051 Georgia Department of Motor Vehicle Safety Capt. Bruce Bugg View
05-0014 Mr. Richard Daley Borden Chemical, Inc. View
04-0203 Chemical Accident Reconstruction Services, Inc. Mr. Michael Fox View
04-0206 Mississippi Tank Company Mr. Mike Pitts View
05-0036 Wiley Rein & Fielding LLP Mr. George A. Kerchner View
05-0009 Fike Corporation Mr. Randy Pettitt View
05-0038 AMTEC Corporation Mr. Michael Penna View
05-0002 Raytheon -SAS Mr. Donald E. Burke View
05-0045 Essex Aerospace and Defense Mr. Russell Zavadil View
05-0032 Seacon Corporation Mr. Sean E. Condren View
03-0263 Clean Harbors Environmental
Services, Inc. 		Ms. Susan J. Sevy View
03-0316 Bechtel Nevada Mr. Jim Przybylski View
05-0022 Manufacturing Company Mr. David H. Baker View
04-0202 Safecraft Safety Equipment Mr. Donald E. Warren View
05-0029 Manufacturers Association (NEMA) Mr. Ric Erdheim View
05-0006 Pro-Pack Testing Laboratory, Inc. Mr. Manuel Rosa View
04-0139 Dukane Corporation Mr. Thomas A. Green View
CHI-05-001 Gebauer Company Daniel J. Van Kuren View
04-0262 Baker Atlas Ms. Shelly Espinoza View
05-0005 Tyco Healthcare/Mallinckrod Ms. April Chance View
04-0284 Mr. Paul Reamy View
04-0286 Kenan Advantage Group, Inc Mr. Bruce Redmon View
05-0011 H.B. Fuller Company Mr. Gene Secor View
05-0019 Florida Power and Light Company Mr. Frank Nesbihal, CHMM View
03-0288 Huntsman Corporation Mr. Philip Abraham View
04-0287 Menlo Worldwide Forwarding Mr. Robert Johnson View
04-0265 Mr. Peter B. O"Connell View
05-0012 Mr. Bob Thompson Mr. Bob Thompson View
05-0024 3rd Combat Communications Group (ACC) Shawntez L. Brooks, 2nd Lieutenant View
04-0275 Ms. Amy Dean View
05-0027 Gabriel Chemicals, L.L.C. r. Jim McDaniel View
05-0008 Mr. Ward Hildreth View